Means for regulating self-inductance in electric circuits.



144743444. PATENTED NOV. 10, 1903. 0. F. BU GEss & B. FRANKENFIELD.MEANS FOR REGUL'ATING SELF INDUGTANOE IN ELECTRIC CIRCUITS.

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No. 748,444. PATBNTED NOV. 10,1903." C. F. BURGESS & B. FRANKENFIELD.MEANS FOR REGULATING SELF INDUCTANCE IN ELECTRIC CIRCUITS.

APPLICATION FILED JAN. 27, 1903.

4 SHEETS-SHBBT 2.

N0 MODEL.

No. 743,444. PATENTED NOV. 10, 1903. G. P. BURGESS & B. FRANKENFIE'LD.MEANS FOR REGULATING SELF INDUGTANGE IN ELECTRIC CIRCUITS.

APPLICATION FILED JAN.Z7,1903.

N0 MODEL. 4 SHEETSSHBET 3.

No. 743,444. PATENTED NOV. 10, 1903.

S & B. PRANKENFIELD.

MEANS FOR REGULATING SELF INDUC'IANCB IN ELECTRIC CIRCUITS.

C. I. BURGES APPLICATION FILED JAN.27,1903.

4 SHEBTS-SHEET 4.

NO MODEL.

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llllm 51 t we u tom attoznup UNITED STATES Patented November 10, 1903.

PATENT OFFICE.

CHARLES FREDERICK BURGESS, OF MADISON, \VISOONSIN, AND BUDDFRANKENFIELD, OF PITTSBURG, PENNSYLVANIA.

MEANS FOR REGULATING SELF-lNDUCTANCE IN ELECTRIC CIRCUITS.

SPECIFICATION formingpart of Letters Patent No. 743,444, dated November10, 1903. Application filed January 27; 1903. Serial No. 140,791. (Nomodel.)

To all whom it may concern:

Be it known that we, CHARLES FREDERICK BURGESS, residing at Madison,county of Dane, and State of Wisconsin, and BUDD FRANKENFIELD, residingat Pittsburg, county of Allegheny,'and State of Pennsylvania, citizensof the United States, have invented certain new and useful-Improvementsin Means for Regulating Self-Inductance in Electric Circuits, of whichthe following is a specification.

Our invention relates to means for regulating the self-inductance inelectric circuits carrying current, including magnetic material, intheir magnet-circuits; and it has for its object to provide means foraccomplishing this general result, broadly considered, whereby suchmeans may be used in many and various relations in connection withelectric circuits toproduce various resnltsthereinsuch, for instance, asregulation of current and pressure in alternating .or varying currentcircuits; and to these ends our invention consists in the means havingthe features of corn slruction and arrangement and mode of operationsubstantially as hereinafter more par ticularly set forth.

While the broad principle involved our invention may be used in many andvarious relations, it is more particularly adapted for use in connectionwith electric circuits as a means for varying the inductance therein forthe purpose of regulating the pressure or current thereof, and it ismore especially useful in connection with -alternating-current circuits,and we therefore will describe our invention generally and in connectionwith alternating-current circuits and as a means for regulating thesame; but it is to be understood that we do not limit our invention byso doing,as we believe our invention is broadly new and that thoseskilled in the art can vary theembodiment of the invention so as toadapt it for many and various uses without departing from the principlethereof, the gen oral and controlling features of which will be setforth herein.

Referring to the accompanying drawings, Figures 1 to 6 are diagrammaticrepresentalions of the hysteresis loop of magnetic induction. Fig. 7 isa detail side view of one form of coil. Fig. 8 is a side view of amechanical structure embodying our invention. Fig. 9 is a transversesection of the same. Figs. 10 and 11 are respectively side and sectionalviews of another embodiment of our invention. Figs. 12, 13, 14, and 15are sectional, detail, side, and plan views of another embodiment of theinvention; and Figs. 16 and 17 are plan views of other modifications.Figs. 18 to are detail views of another modification. A

In our Patent No. 720,884, dated February 17, 1903, we disclosed amethodof regulating electric circuits by varying the inductance in thecircuit, such circuit including the resultant inductance due tosuperposing two magnetizations on a core of magnetic material, 'and theresultant inductance inthe circuits illustrated was due, further, tosuperposing an alternating-current magnetization and adirectmagnetization upon the same core of magnetic material. Ourpresentinvention relates to the same general subject-matter and was disclosedto a greater or less extent in said application, but was not claimedtherein,and our invention consists, further, in means for regulating theself-inductance in an electric circuit or circuits arranged in magneticinductive relation to magnetic material and at the same time preventingmutual inductance between the regulated and the reg ulating circuits,whereby the advantages of our method disclosed and claimed in our former application may be secured in the most satisfactory manner.

When a piece of magnetic material is magnetized by an alternatingcurrent, the wellknown hysteresis loop (shown in Fig. 1) is describedduring each cycle. Let 0 O represent the maximum instantaneous value ofthis current, and B B the total change in magnetization caused byvariation of the current from the maximum positive value 0 C to an equaland maximum negative value Now suppose that the same magnetic materialis initially magnetized bya direct current toa point 0', Fig. 2, on themagnetization curve, which is represented by the dotted curve 0 O B. Thepoint 0' then represents an amount of magnetization (J 9 produced by acurrent 0 C. If an alternating 2 mates current of the same vvalue asbefore he usedto magnetize the material in the same linear direction asthe direct current, G c and C 0 will represent its equal maximuminstantaneous values, and the total change in mag-' netism caused by thevariation from the maximum positive value C c to an equal maximumnegative value 0 c of the alternating current will be represented by thedistance B B. The same number of magnetizing turns are assumed for thealternating current in Figs. 1 and 2 and for the direct current in Fig.2, and the magnetism is taken in the same direction and in the sameplane in both figures. It will be noticed that the range of variation BB is greater in Fig. 1 than in Fig. 2. In other words, theself-inductance for a complete cycle will be greater for the conditionsrepresented by Fig. 1 than in FI 2. When the self-inductance is variedby this means, the two magnetizations being in the same plane and in thesame direction, the alternating current induces in the directcurrentcircuit an alternating electric pressure after the manner of the actionof the primary of a transformer on its secondary. in many practicalapplicationsit is desirable to avoid this transformer action, and to doso the two magnetizing-coils must be so placed that their mutualinductance is zero. it is furthermore necessary that the variation ofmagnetism represented by the distances B B in Figs. 1 and 2 be regulableby change of the direct magnetization with this arrangement of thecoils.

We have discovered that when the magnetic core is subjected tomagnetization by a direct current, which magnetization is' at rightangles to the magnetization due to an alternating current, the range ofmagnetization is reduced as before, and its value is regulable by achange in value of the direct current. his well known that twomagnetizing-coils may be arranged to produce magnetizations at rightangles to each other in the same magnetic material with a mutualinductance of zero between the coils, and it follows theoretically aswell as practically a most efficient means for producing these resultsconsists, broadlyspeaking, in a magnetic core having two independentelectric circuits-arranged in magn tic inductive relations thereto andin the non-inductive relations to each other, or, in other words, thetwo independent electric circuits are arranged at right angles to eachother magne ically, so as to have no mutual inductance, while at thesame time they are in magnetic inductive relation to the core. I

'lhe advantages of reducing or practically eliminating the mutualinductance between the two circuits in magnetic inductive relations withthe core are apparent to those skilled in the art.

it is manifest that many and various structural devices maybe made whichwill embody the principle of our invention and secure the oi thealternating coil.

advantages thereof to a greater or less degree, and without attemptingto illustrate all the various forms or embodiments of our invention'wewill now proceed to describe several typical embodiments, it beingunderstood that our invention, broadly considered, is not limited to thespecific structures set forth.

In Figs. 7, 8, and 9 we have illustrated an embodiment of our invention,in whichA represents a coil of insulated wire in the form of a ring, andthis coil is bound or surrounded by some insulating material, (shown inthe present instance as the cord a,) and this constitutes one of theelements of our apparatus and is shown as adapted to carry alternatingcurrents and will be referred to as the alternating-current coil orcircuit. in these figures the direct-current coil or coils B are made inany suitable way and are adapted to thread or linlr the alternatingcurrent coil A, and in this instance we have shown a number ofdirect-current coils B, connected together in series by theconductor b.The core of magnetic material C in this instance is made up of a numberof plates or laminae c, which are arranged on either side of thealternatingcurrent coil A and are preferably-provided with-ventilators0', while the space between the adjacent faces of the side groups oflamihated plates on each side of the alternating coil is filled withrings, thin cylinders, or laminations C, the laminations beingtransverse to the alternating coil A, while the laminations c are inplanes parallel to the face lhe direct-current coils in the presentinstance are of such a shape as to fit the core 0., made up in themanner above described. in order to hold the iaminm together, we providea support or clamp of non-magnetic material, shown in the presentinstance as composed of a ring D, having on one side inward extensionsD, and an annular plate D also having inward ere tensions D and theparts may be secured together in any desired way, as by means of boltsD. in this way a very compact and effective device can be made, and itwill be seen that the direct-current coils B are arranged so that theircommon magnetic cin cuit crosses that of alternating-current coil Apractically at right angles and that the mutual inductance between thecoils is'eliminated. The core being made of laininations is cheap andeffective and provides, through the medium of the windows or openings,sufficient ventilation, and they are arranged so as to form an air-gap 0which is advantageous or necessary to prevent induced currents in theiron. it will thus be seen that the device comprises several elements,an

alternating-current coil, one or more directcnrrent coils, a core ofmagnetic material surrounding the alternating-current coil andsurrounded by the direct-current coil or coils, and a suitable clamp orframe to hold the parts together.

in Figs. 10 and it another embodiment of our invention is shown, and inthis case the alternating-current coil A is arranged substantially asbefore stated and is bound with a cord at and surrounded by the core 0,made up substantially as before described, except that in this instanceanother air-gap is arranged between the transverse laminations and theflat laminations, so as to adapt the device for regulating a circuit forconstant current. This gap may be so proportioned that the alternatingcurrent when the apparatus is the only thing in circuit with thegenerator will just equal in value the value of the constant current..In this embodiment there is a single direct-cu rrent coil B, which iswound in any desirable manner and which links the alternating-currentcoil and the magnetic core in the manner clearly shown, and the frame orclamp D consists, essentially, of two spider frames secured by bolts 01or otherwise and arranged in the opening of the alternatingcurrent coil,with the fingers projecting outward. By the term link used herein inconnection with lines of force is understood to be meant the circuitingof the lines'of force through the coil 'and completing themselvesoutside in the same manner as the link of a common chain'circuitsanother link.

While in the two forms of embodiments so far described "we havedescribed the coil A as the alternating-current coil and have surroundedthis by the direct-current coil or coils, it is to be understood thatthe inner coil could be used as a'direct-current coil and the outer orsurrounding coil as the alternating coil. In either case the core ofmagnetic material can be the same as that heretofore described; but theair-gap for preventing induced currents in the core will in the lattercase be located so as to break the continuity of the metal in themagnetic circuit about the coil A. The gap a Fig. 11, would serve thispurpose, the coil B in this case serving as the alternating-currentcoil. ,It used for a constant current, the radial air-gap 0 Fig. 10,could then be so proportioned as to maintain the current at the requiredvalue when the apparatus only is in circuit with a source of constantpressure and frequency.

In Figs. 12, 13, 14, and 15 we have illustrated another constructionembodying our invention, in which A represents the alternating-currentcoil, and B the direct-current coil, arranged at right-angles to eachother, and surrounding these coils is core 0, of magnetic material. Thiscore can be made up of a series of stampings, (shown in detail inFig.13,) so that practically there is but one form of stamping to makeup the whole core. In Figs. 16 and 17 is shown another embodiment wherethe parts are lettered as before, but in which there are twodirect-current coils B, arranged at right angles to thealternatingcurrent coil or coils A, and the core C is made up ofsectional stampings, as indicated.

Still another modification of our invention is shown in Figs. 18 to 25,inclusive. In this construction there is shown a plurality ofalternating-current coils A and a plurality of direct-current coils B,so placed that the lines of force set up by the alternating-currentcoils do .notlink any of the direct-current coils and so that the linesof force set up by the direct-current coils do not link any of thealternating-current coils-in other words, so that the mutual inductanceis zero. The magnetic circuits are in the same planewith regard to thecore, and this plane is parallel to the direction of the laminations.The core consists of two sta'mpings, as an outer ring 0, fittingcircumferentially an inner disk 0,

and appropriate openings 0", Figs. 21, 22,23,

24, and 25,- are provided either inthe ring or in the disk for thecoils. In this construction the coils of the alternating-current and thedirect-current circuits overlap and are connected in series, asindicated in Fig. 18, but they do not link. In this figure the full lineA represents the alternating-current circuit and the dotted lines B thedirect-current cir-. cuit. The coils consist of one or more turns ofinsulated conductor and are placed ninety degrees apart magnetically, sothat the mutual inductance between the circuits is zero. The core, asbefore, is laminated and made oftwo punchings, and either the ringportion 0 or. the disk portion 0' may be provided with notches, asindicated in Figs. 21, 22, respectively, and the coils or windings areplaced in the notches of the core, and each. notch contains parts of twocoils of the same circuit, alternating notches being used for thediiferent circuits, as shown in Figs. 18 and 19. The device may beprovided with a circumferential or annular air-gap c, Fig. 23, foradaptation of the device for constant-current working, or radialair-gaps c 0 may be formed in the stampings and so placed that theair-gap inductance is in the alternating magnetic circuits only. In thestructure thus described there may be any appropriate clamping devicefor holding the laminations, which need not be described.

While we have spoken of certain coils as being alternating-circuit coilsandothers as direct-circuit coils, it is evident that either set of'coils may be used for either purpose.

These illustrations are suificient to define the general character ofdevices embodying our invention, and we may refer to our formerapplication as embodying some other forms at right angles magneticallyto each other and in such a way that the lines of force set up by onecoil will not link, thread, or pass through the turns of the other coil,and any such arrangement of the coils at less than a right angle to eachother magnetically will be lessefiective in eliminating the mutualinductance, but may eliminate it to a greater or less extent. It is alsomanifest'from the above that a single alternating-current'coil or aplurality thereof ora'single direct-current coil or plurality thereofmay be used, according to the exigencies of any particular case, and inour claims where we use the term coil it is to be understood that itembraces a single coil or a plurality of coils; It is fur ther to beunderstood that While we have defined'one coilas an alternating-currentcoil and another as a directcurrent coil either coil may be suppliedeither with direct, current, alternating current, or varying current,according to the particular application to which the invention is made.to be understood that in referring to the elimination of mutualinductance we do not confine ourselves necessarily to absoluteelimination, but rather to minimization of mutual inductance to such anextent that it will not be a disadvantage in the operation for anyparticular purpose. I n other words, the plac ing of the coils so thatthey would be not quite but almost at magnetic right angles would beincluded in this specification and claims.

Where we speak of a coil in the specification and claims wemean either asingle coil-or a multiplicity of coils consisting of turns of wire orconducting material.

It will'be understood that the electric current in the circuit in whichwe regulate the self-inductance may be. direct, alternating, pulsating,or irregular, and the same may be said of the electric current in theregulatingcircuit. It will be further understood that where herein it isstated that the current in one circuit may be varied at will, by thisterm it is meant that the current may be varied to produce the desiredresults, whether it be done by hand or by automatic devices.

"What we claim is- 1. As a means for regulating self-inductance inelectric circuits, a core of magnetic material, and twoindependent'electric circuits in magnetic inductive relation to the coreand in non-inductive relation to each other, the current in one circuitbeing varied at will.

2. As a means for regulating self-induct- I ance in electric circuits, acore of magnetic material, and two independent electric circuits inmagnetic inductive relation to the core and in non-inductive relation toeach other, one of the independent'electric circuits carryingalternating currents, the current in one circuit being varied at will.

3. As a means for regulating self-inductance in electric circuits, acore of magnetic material, an electric circuit including a coil It isfurther Y in magnetic inductive relation to the core,

and another electric circuit including a coil also in magnetic inductiverelation to the core and in non-inductive relation to the coils of thefirst circuit, the current in one circuit being varied at will.

4. As a means for regulating self-inductance in electric circuits, acore of magnetic material, and two independent electric circuits inmagnetic inductive relation to said core and in non-inductive relationto each other, the magnetization of one circuit being in a plane atright angles magnetically to the other, and the current in one circuitbeing varied at will.

5. As a means for regulating self-inductance in electric circuits, acore of magnetic material, and two independent electric circuits inmagnetic inductive relation to said core and in non-inductive relationto each other, the magnetization of one circuit being in the same planebut at right angles magnetically to the other, and the current in onecircuit being varied at will.

6. As a means forregulating self-inductance in electric circuits, a coreof magnetic material, and two independent magnetizingcoils in magneticinductive relation to said core and arranged in a manner that the linesof force setup by one coil will not link the turnsof the other coil, thecurrent in one circuit being varied at will.

7. As a means for regulating self-inductance in electric circuits, 3.core of magnetic material, and two independent electric circuits inmagnetic inductive relation thereto and in non-inductive relation toeach other, one of which is an alternating-current circuit and the othera direct-current circuit, the direct current being varied at will.

8. A. means for regulating self-inductance in an electric circuit,comprising two magnetizing-coils, one of the coils carrying alternatingcurrents and the other direct currents, a core of magnetic materialinterposed between the coils, and a frame supporting the same.

9. A means for regulating self-inductance in an electric circuit,comprising a magnetizing-coil carrying alternating currents, a laminatedcore of magnetic material surrounding said coiland provided withventilating-openings, a series of magnetizing-coils carrying directcurrents surrounding the core, and a frame supporting the same,substantially as described.

10. A means for regulating self-inductance in electric circuits,comprising a coil, a core surrounding the same and provided with anair-gap, and another coil surrounding the core.

11. A means for regulating the self-ind uctance of a coil carrying analternating or varying electric current and including magnetic materialin its magnetic circuit by independent magnetization of the samemagnetic material by another coil carrying an electric current (whichmay be direct, alternating or va- ElO rying) and so placed with relationto the first coil and the magnetic material that there is no mutualinductance between the two coils.

12. A means for regulating the self-inductance of a coil carrying analternating or varying electric current and including magnetic materialin its magnetic circuit by independent magnetization of the samemagnetic material by another coil'carrying an electric current (whichmay be direct, alternating or varying') and so placed with relation tothefirst coil and the magnetic material that the lines of force ofeither coil do notlink the other coil.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

CHARLES FREDERICK BURGESS. BUDD ERANKENFIELD. Witnesses to signature ofCharles Frederick Burgess;

W. D. HIESTAND, FANNIE G, SANFORD. Witnesses to signature of BuddFrankenfield:

H. A. CROOKS, TJHos T. THOMAS.

